Remove everything but markdown from third_party

third_party/pkg/js/lib/src/wrapping/magic_proxy.dart

Index: third_party/pkg/js/lib/src/wrapping/magic_proxy.dart
diff --git a/third_party/pkg/js/lib/src/wrapping/magic_proxy.dart b/third_party/pkg/js/lib/src/wrapping/magic_proxy.dart
deleted file mode 100644
index d20ff40cfac3bd9a1c9c634b8324e88556535424..0000000000000000000000000000000000000000
--- a/third_party/pkg/js/lib/src/wrapping/magic_proxy.dart
+++ /dev/null
@@ -1,20 +0,0 @@
-// Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
-// for details. All rights reserved. Use of this source code is governed by a
-// BSD-style license that can be found in the LICENSE file.
-
-part of js.wrapping;
-
-/// base class to simplify declaration of [TypedProxy].
-class MagicProxy extends TypedProxy {
-  MagicProxy([Serializable<FunctionProxy> function, List args])
-      : this.fromProxy(new Proxy.withArgList(
-            function != null ? function : context.Object,
-            args != null ? args : []));
-  MagicProxy.fromProxy(Proxy proxy) : super.fromProxy(proxy);
-
-  operator[](arg) => $unsafe[arg];
-  operator[]=(key, value) => $unsafe[key] = value;
-
-  @override noSuchMethod(Invocation invocation) =>
-      $unsafe.noSuchMethod(invocation);
-}